1. Field of the Invention
The present invention relates to a metering end-fitting for dispensing a fluid product in the form of doses of predetermined volume, especially a cosmetic product such as a shampoo, a conditioner, a gel, a lotion, a milk, etc. The invention also relates to a packaging and dispensing assembly fitted with a metering end-fitting according to the present invention.
2. Description of the Related Art
In the cosmetics field in particular, many hair products, particularly shampoos, are packaged in containers having deformable walls, the neck of which is closed off by a wall pierced at its center with one or more small holes for expelling the product. In order to dispense the product, the container is turned upside down and pressure is exerted on the deformable walls of the container to allow the product to be forced through the hole or holes. The product is collected in the palm of the user""s hand and applied to his or her hair. However, this simple hand movement does not allow the amount of product dispensed to be metered.
Admittedly, there are devices for metering a product to be dispensed, but they are of such complexity that their cost is completely inappropriate to the economic requirements of certain distribution channels, particularly the mass market.
U.S. Pat. No. 5,090,600 describes a metering end-fitting of the type having a metering chamber formed inside a piston, a free end of which is provided with openings capable of allowing the metered expulsion of the product. The openings in the metering chamber are exposed by means of pressure exerted by the product on one face of the piston. The product then flows under gravity while the openings are exposed. When expelling the product, the closure element substantially emerges from the metering chamber. One of the problems associated with such a design stems from the fact that the element ensuring closure of the outlet holes in the metering chamber forms one piece with the piston. Consequently, the amplitude of the movement of the closure element is identical to the amplitude of the movement of the piston. Expulsion of a large dose of product requires a large-amplitude movement of the closure element, and so a bulky dispensing head with a closure element which, in the dispensing position, emerges considerably outside the metering chamber. Such a design is relatively detracting from an aesthetic standpoint, particularly when used for the packaging of cosmetic products. An alternative would consist in using a metering chamber having a larger cross section so that expulsion of the dose requires a shorter travel by the piston, and therefore by the closure element, but to drive the piston would require a high pressure which would be incompatible with the constraints relating to the use of cosmetic products.
Furthermore, although such an end-fitting is particularly appropriate for the metered dispensing of readily flowable liquid products such as drinks, it cannot be easily used for dispensing viscous liquid products, such as those commonly used in the cosmetics field. This is because the viscosity of these products does not permit the dose of product to flow sufficiently rapidly, merely under its own weight. Furthermore, the openings are formed from holes pierced in the wall of the metering chamber, and are therefore oriented radially with respect to the cross section of the metering chamber. Thus, at expulsion, the product leaves with an essentially radial component, which may be acceptable when the product flows solely under its own weight. On the other hand, such radial expulsion is completely unacceptable when the product leaves under pressure since it becomes difficult to gather the dispensed product in a localized manner.
U.S. Pat. No. 2,904,227 describes an end-fitting for metered dispensing of a product, which comprises a metering chamber inside which a piston is slidably mounted. Passing through the piston is an axial channel which terminates near the free end of the piston in a radial portion opening onto an outlet hole. In the rest position, the outlet hole is closed off. In order to dispense a dose of product, the outlet hole is exposed due to the pressure of the product being exerted on the piston. The product flows through a radial portion of the channel, passes into the axial part of the channel and leaves through the radial outlet hole. In the same way as for the device of U.S. Pat. No. 5,090,600, expulsion of the product is accompanied by a movement, outside the metering chamber, of a closure element integral with a piston, the amplitude of the movement depending on the dose to be dispensed.
Furthermore, in the same way as for the device of U.S. Pat. No. 5,090,600 the product leaves with a very large radial component, which does not allow localized dispensing of the product. In particular, in the case of a cosmetic product, it is difficult to collect the dispensed product in the palm of one""s hand. Furthermore, the necessary passage of the product through the axial channel inside the piston makes the device particularly unsuitable for high flow rates, in particular for products having a high viscosity. In addition, such an axial channel is subject to fouling, in particular after a long period of non-use, which may make the device completely unusable.
One of the objects of the invention is to provide a metering end-fitting which completely or partly solves the aforementioned problems.
A further object of the invention to provide a metering end-fitting in which the movement of the closure element, closing off an outlet passage of the metering chamber, is not linked to the volume of the dose to be dispensed so that, even for doses of large volume, the movement of the closure element, especially outside the metering chamber, has a limited amplitude.
Yet a further object of the invention to provide a metering end-fitting which can be easily used and has a low manufacturing cost.
Another object of the invention to provide a metering end-fitting which is particularly suitable for the metered dispensing of products having a high viscosity.
Yet another object of the invention to provide a metering end-fitting which allows the metered and localized dispensing of a product under pressure.
According to the invention, these and other objects are achieved by a metering end-fitting intended to be mounted on a container containing a product, and comprising a metering chamber inside which a piston is slidably mounted, the piston being mounted so as to be able to pass from a first position in which the metering chamber has a maximum volume to a second position in which the metering chamber has a minimum volume. The metering chamber comprises at least one inlet passage which is open when the piston is in the first position and closed in a substantially sealed manner when the piston is in the second position, the piston being coupled to a closure element which, in the first position of the piston, closes off, in a substantially sealed manner, at least one outlet passage in the metering chamber and frees the outlet passage when the inlet passage is closed, the closure element moving with a shorter travel than the travel of the piston.
In practice, the closure element moves with a travel corresponding approximately to the axial height of the inlet passage, during which travel the closure element ensures that the outlet passage in the metering chamber is kept substantially closed as long as the inlet passages in the metering chamber are open. Next, once the or each outlet passage is exposed, the closure element is immobilized. From that moment on, only the piston moves inside the metering chamber so as to expel the dose that it contains. In other words, the closure element is integral with the piston only over a portion of the piston""s travel. Thus the dispensing of doses of larger volume is permitted, while limiting that portion of the closure element which emerges out of the metering chamber when dispensing the dose. Thus, the aesthetic appearance and the practicality of the assembly produced are improved.
In a simplified manner, the piston defines, in combination with the closure element, a wall whose first face communicates with the container and whose second face (at least partly) communicates with the metering chamber. When dispensing the dose, the pressure of the product is first exerted on the wall portion corresponding to the closure element and continues until the inlet passages in the metering chamber are closed off. During this first phase, the closure element drives the piston towards the outlet passage in the metering chamber. Next, when the inlet passage in the metering chamber is closed and the outlet passages in the metering chamber are exposed, the closure element is immobilized. The pressure of the product is then exerted on the piston itself, which moves independently of the closure element until it reaches the second position.
Advantageously, the outlet passage and the closure element are arranged so that the product leaves the metering end-fitting in at least one stream with an essentially axial component. Typically the outlet passage is produced between the closure element and an opening formed in a wall of the metering chamber on the opposite side from the inlet passage. Thus, by modifying the number of passages and their size, it is possible to vary to a large extent the output flow rates of the product. In the case of a closure element in the form of a cylinder of revolution, it is possible to define for the product one or more flow passages which can extend over an angle that can vary from 1xc2x0 to 360xc2x0. This flexibility permits the dispensing of products which have a viscosity chosen in the range going from very free flowing products to very viscous products, such as shampoos or gels.
In addition, with pressure being exerted under normal conditions of use, the product is expelled essentially along an axis, in this case the axis of the metering chamber. This essentially axial expulsion of the product makes it possible to collect it easily, especially in the palm of one""s hand in the case of a shampoo. The manufacturing cost is compatible with the economic requirements of the mass market insofar as such an end-fitting consists of a limited number of parts whose production, especially by molding, does not involve the use of complicated and expensive molds. Typically, for a shampoo, the volume of the metering chamber is about 5 ml.
According to a preferred embodiment, a stop is provided in order to limit the travel of the closure element when the outlet passage is in the open position.
The stop may be located outside the metering chamber. Alternatively, the stop is provided on the closure element itself, and in this case inside the metering chamber.
According to a preferred embodiment, the metering chamber has a free end opposite the inlet passage, the outlet passage being set back with respect to the free end, the stop being arranged in such a way that, in the open position of the outlet passage, the closure element does not project substantially from the free end. Thus, the aesthetic appearance of the end-fitting, produced as one structure, is improved and the consumer does not see any apparent modification from the storage position to the dispensing position. Furthermore, with such a configuration, the outlet passage is located approximately at the bottom of a recessed portion formed by the metering chamber. This configuration helps to further improve the axial expulsion of the product which is guided inside the walls of the recessed portion. This advantage is particularly appreciable when the consumer exerts a large force on the walls of the bottle in order to expel the dose.
The walls of the recessed portion may furthermore guide that portion of the closure element which moves outside the metering chamber, ribs being advantageously provided for this purpose. These ribs furthermore define channels for conveying the product from the outlet passage towards the end of the metering chamber.
Advantageously, an external cover fits onto the metering end-fitting, the cover having at least one hole which is preferably located opposite the outlet passage, the stop consisting of a portion of the external cover. Apart from the stop function, the cover helps to improve the aesthetic appearance of the assembly. This external cover furthermore allows the characteristics, especially the dimensional characteristics, of the stream(s) of product dispensed to be varied.
Advantageously, an elastic return element is provided for returning the piston to the first position when the pressure of the product on the first surface of the piston is released. This return element, which is preferably a helical spring, facilitates the operation of the assembly. After a dose has been dispensed, no manipulation is needed for preparing the assembly for dispensing a new dose.
Alternatively, it is possible to provide for the return of the piston to take place manually by pressure exerted on the free end of the closure element, or when fitting a removable cap onto the metering end-fitting.
Preferably, an element is provided for driving the closure element into its position for closing off the outlet passage during the return of the piston to the first position, especially under the action of elastic return. By way of example, the driving element may consist of a stop provided on the closure element, and with which the piston is capable of coming into engagement.
Preferably, the container has deformable side walls, the pressure of the product on the first surface of the piston being obtained by exerting pressure on the walls. Air is allowed to enter the container when the pressure on the walls is released so as to compensate for the reduction in volume of product inside the container, after a dose of product has been dispensed. This configuration has the advantage of permitting a hand movement similar to the conventional hand movement used in the cosmetics field.
Preferably, the intake of air takes place, during the return of the piston to the first position, via the outlet passage in the metering chamber, before it is closed by the closure element. The construction of the assembly is thus facilitated by dispensing with a separate circuit for the air uptake.
According to a preferred embodiment, the inlet passage extends over an axial height such that, over a first part of the travel of the piston between the first and second positions, the inlet passage is open so as to allow substantially complete filling of the metering chamber, the closure element being arranged so that the outlet passage in the metering chamber is closed off when the piston moves over the first part of its travel. This makes it possible, in the case of a viscous product, to always be able to substantially fill the entire metering chamber, most particularly in the case of dispensing a viscous product, in a short time after a previous dispensing operation. This is because a highly viscous product, flowing under gravity, would be unable to have enough time to completely fill the metering chamber. With this advantageous characteristic of the invention, the gravity filling of the metering chamber is supplemented by pressurized filling, which takes place, as required, right at the start of a dispensing phase. More specifically, a plurality of such inlet holes are used, these being arranged in a uniform manner all around the periphery of the metering chamber.
According to a specific embodiment, the closure element has a first portion adjacent to the inlet passage and a second portion located on the opposite side from the inlet passage, the second portion having a larger cross section than the cross section of the first portion and extending over an axial height approximately equal to the axial height of the inlet passage so as to close off the outlet passage over the first part of the travel of the piston.
Preferably, the first and second portions are cylindrical in shape and separated from each other by a frustoconical portion. Thus, an annular outlet passage is defined when the opening made in the metering chamber lies opposite the frustoconical portion or of the cylindrical portion of smaller cross section. Such a geometry makes it possible for there to be a uniform stream of product all around the closure element, in the manner of a tube, the axial component of which is further enhanced, the frustoconical portion forming a ramp for the product so as to guide its flow in a substantially axial manner.
According to a preferred embodiment, the metering chamber is arranged annularly all around the closure element, the closure element being centered on the longitudinal axis of the metering chamber. Advantageously, the chamber and the closure element are of circular cross section. Although a circular cross section is preferred, any other cross section could be used, particularly a square, triangular, hexagonal, oval, star-shaped or other cross section. Likewise, the closure element may be provided so as not to be centered on the axis of the metering chamber.
The metering end-fitting according to the invention may be fixed, especially by bonding, snap-fastening or screwing, to a neck formed on the container. The fitting may also result from force-fitting inside the neck of the container. Preferably, the metering end-fitting according to the invention is obtained by molding a thermoplastic, especially one chosen from polypropylenes or polyethylenes.
According to another aspect of the invention, an assembly is also produced for the packaging and metered dispensing of a product, especially a cosmetic product, comprising a container formed from a body which has one end closed by a bottom, the other end forming a neck, a free edge of which defines an opening, a metering end-fitting according to the invention being fixedly mounted on the neck. The container may be in the form of a tube or a bottle. It may have any cross section, in particular an oval, elliptical or circular cross section. A cap may be provided for removably covering the metering end-fitting, especially in the storage position. Advantageously, the metering end-fitting is mounted along the axis of the container. However, this is not a necessary characteristic. In some cases, it may be desirable to mount the metering end-fitting at an angle with respect to the axis of the container so as to improve the degree of draining of the container.
Advantageously, the body has side walls capable of deforming when pressure is exerted on them and of returning to their initial shape when the pressure is released. Typically, the pressure is exerted in a direction perpendicular to the side walls.
Such an assembly is particularly suitable for the packaging and metered dispensing of a cosmetic product, especially a shampoo, a conditioner, a hair gel or a beauty milk or cream.